Top supported coolant hood



Sept. 16, 1969 v J. M. SUDDARTH 3,466,311

TOP SUPPOBTED COOLANT HOOD Filed Oct. 28. 1966 M X INVEN TOR F/6.4IBYFWM/ A T TORNFYS '1 JACK M. SUDDARTH United States Patent 3,466,811TOP SUPPORTED COOLANT HOOD Jack M. Suddarth, Muskogee, Okla., assignorto Coburn Manufacturing Company, Inc., Muskogee, Okla., a cororation ofOklahoma P Filed Oct. 28, 1966, Ser. No. 590,396

Int. Cl. B24b 55/02, 55/04 US. Cl 51266 Claims ABSTRACT OF THEDISCLOSURE This invention generally relates to a cover for a grindingchamber wherein coolant fluids are used and more specifically relates toa movable cover supported at its top and having a positive sealthroughout its movement. Because of the large amount of coolant fluidsused, the cover finds particular utility in apparatus for grindingophthalmic lenses.

Prior art covers have displayed several disadvantages. For the most partthey have been bottom supported and movable on tracks which becomeclogged with grinding particles. Additionally, the prior art deviceshave been lacking in an efiicient positive seal for keepingfurnesdeveloped from the heated coolant from contaminating the atmosphere nearthe machine operator.

In general, a slotted skirt assembly is rotatably supported from itsupper central surface. The bottom edge of the depending skirt fits intoan annular lubricating groove in the base pan. In operation, the skirtis locked in place by insertion of a work hold ng chuck through anaperture in the skirt. The sweeping movements of an abrading tool whichis inserted through the base pan cause the base pan to rotate about acentral vertical axis relative to the aforesaid skirt. The abrading toolwill thus move through the slot in the skirt. In order to prevent escapeof the fluid generated within the grinding chamber from the slot withoutincreasing the drag on the sweep generator motor, a pair of negators areprovided. One end of each negator is secured to the stationary skirt whle the other end is secured to spools which are moving with the oil pan.n

An important objective of the present invention IS tO overcome thedisadvantages of the prior art and provide a movable cover which willnot become clogged by grinding particles. l

A further objective of this invention is to provide a movable coolanthood which will eflectively prevent escape of fumes to the atmosphere Ayet further objective of this invention is to provide a movable coolanthood having means for maintaining constant rotational bias whilesimultaneously rolling and unrolling opposite sides of the cover.

These and other objectives of the invention will become more apparent tothose skilled in the art by reference to the following detaileddescription when viewed in light of the accompanying drawings, whereinlike elements throughout the figures thereof are indicated by likenumerals and wherein:

FIGURE 1 is an exploded view of the cover of this invention;

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FIGURE 2 is a rear elevation view of the upper skirt assembly of FIGURE1;

FIGURE 3 is a bottom plan view of FIGURE 2; and,

FIGURE 4 is a section taken along line 44 of the upper skirt assembly inFIGURE 1.

In the embodiment described, the cover of this invention is designed forlens grinders of the type which have a work holding chuck which ismovable longitudinally into and out of a grinding chamber which houses arotating abrading tool. Lens grinders of this type incorporate a sweepgenerator motor for moving the abrading tool through a grinding sweeppast the lens blank. Such lens grinders are well known in the art andare described in US. Patent 2,806,327 to O. W. Coburn, dated Sept. 17,1957, and in copending application Ser. No. 495,827, filed Oct. 14,1965, by Jack M. Suddarth et a1.

Referring to FIGURE 1, the numeral 10 generally indicates a base memberof a grinding chamber while the numeral 12 generally indicates an upperskirt assembly. The base member 10 has a horizontal bottom plate or oilpan 14 one end of which defines a half-circle. Extending verticallyupwards from the other end of the oil pan 14 is a support member 16comprised of a back plate 18, side walls 20 and 2G, and an inwardlydirected top bearing surface 22. An aperture 24, large enough to receivea conventional abrading cup is located in the central portion of backplate 18. The inner portions of side walls 2040' are bent inwardly at 26and 26' respectively. Located at opposite ends of the inner side of thetop bearing surface 22 are semi-circular recesses 28 and 28. A flange 30extends vertically upward from the periphery of the oil pan 14 andthereby defines a shallow oil coolant retainer chamber 31 with acircular ridge 32 of pan 14 which is spaced inwardly from flange 30.Depending downwardly from the bottom surface of the pan 14 and locatedcentrally of circular ridge 32 is a projection 33. The projection servesto rotatably support the base member 10 on the tool holding assembly ofthe lens grinder.

A fluid supply housing 34, with attached nozzles 36 and 38, is securedto the pan 14. The nozzles 36 and 38 direct a lubricating coolant fluidonto the workpiece during grinding. A conventional supply means toinclude a reservoir, pump, and supply line leading to the housing 34 canbe located without the base member 10. Since it forms no part of theinstant invention, it is not shown or described. A passageway or fluidoutlet 39 for exhausting the oil and accumulated grinding particlesextends from adjacent the inner portion of the ridge 32 down through thepan 14 to a suitably disposed exhaust pipe (not shown). It should benoted that the coolant in pan 14 is maintained at a level correspondingto the height of ridge 32 since it must spill over the ridge prior toreaching exhaust aperture 39.

The top cover 12 is comprised of a circular skirt 40 which is rigidlysecured to, and depends downwardly from, the outer periphery of acircular plate 42. A shaft 44 is rigidly secured to the center of theplate 42 and extends vertically upwards therefrom.

The plate 42 and depending skirt 40 are rotatab y supported from aboveby a support arm 46. The support arm 46 is of triangular shape, and hasa circular opening 48 formed at one vertex by arcuate clamping arms 50.The arms 50 closely surround a bearing sleeve 52 and may be adjusted torigidly clamp the sleeve by means of an adjusting screw 54. The sleeve52 is rotatably received on the shaft 44. An enlarged supporting rim 56is formed circumferentially about the upper portion of the shaft 44. Theside of the support arm 46 opposite the vertex opening 48 has adownwardly depending flange 58 which is supported on and rigidly securedto the bearing surface 22 by screws 59. The inner side 60 of the flange58 is spaced from the skirt 40 to allow free relative movementtherewith.

Spools 62 and 62' are each located with one of their ends rotatablysecured at opposite ends of the flange 58 and depend downwardlytherefrom. The exact location of the aforesaid spools is such as to beconcentric with the semicircular openings 2828 when the member 58 issecured to the bearing surface 22.

An aperture 64, large enough to freely receive the work holding chuck(not shown), is located centrally of the skirt 40. Resilient sealingflaps 66 extend from the circumference of the aperture 64 inwardlytoward its center. The flaps 66 will engage the periphery of the workholding chuck and will keep the work sealed from the atmosphere. Acircular ring 70, rigidly secured to the skirt 40 about thecircumference of the aperture 64, secures the flaps 66.

A slot 72 extends circumferentially in the skirt 40 from adjacent oneside of the aperture 64 continuously to a point adjacent the other sideof the aperture 64. The height of the slot 72 is at least as great asthe diameter of the aperture 24. As best seen in FIGURE 2, the lowerportion of the skirt 40 below the slot 72 and opposite the aperture 64is removed to leave an opening 73 which is wide enough to permit upwardremoval of the upper skirt assembly 12 when the abrading tool supportarm is inserted.

Two negator members 74 and 74 are attached to skirt 40 on opposite sideof opening 64 to bias the skirt to its central position (FIGURE 1)whereby the opening will always center itself to receive the work chuck.Negators are used so that the bias will be uniform throughout themovement of the skirt. For the sake of convenience and clarity indiscussion, only one negator 74 will be discussed, but it is to beremembered that the structure and manner of engagement of negator 74 issymmetrical to negator The negator 74 is an elongated strip of metalwhich has one end secured to the skirt 40 at a point between theaperture 64 and the end of the slot 72 by a strip '75. The other end ofthe negator 74 is secured to the rotatable spool 62 and is wrappedtherearound in such a manner that, as viewed in FIGURE 3, when it isunrol ing the spool 62 will rotate in a clockwise direction and whenrolling up the spool will rotate in a counterclockwise direction. Theportion of the negator 74 between the strip 75 and a plane passedthrough the vertical centerline of the cover 42 and the spool 62conforms closely to the outer surface of the skirt 40 and seals the sot72 from the atmosphere. As mentioned above, the negator 74 issymmetrical to the negator 74 and therefore the spool 62 will rotatecounter-clockwise when unrolling and clockwise when rolling up. Thenegator 74 is of suflicient width and length to completely cover thatportion of slot 72 which, during normal operation, will extend betweenthe strip 75 and the aforesaid p ane.

Referring to FIGURE 3, if the skirt 40 moves clockwise relative to thesupport arm 46, the negator 74 will roll up around the spool 62 aspecified amount while the negator 74 will unroll from the spool 62' alike amount. The use of negators allows a roll-unrol relationshipbetween spools without changing the bias against further movement ineither direction. In other words, there is a constant torque takeup andthe bias against torque is the same in any position of the skirt 40.

In the assembled position, the skirt 40 is supported so that its bottomedge projects into the coolant chamber formed by the ridge 32 and skirt30 but does not contact the pan 14. The aperture 24 is substantiallyopposite the aperture 64. The pan 14 is maintained with a level of oilwhich is between the height of the ridge 32 and the height of the skirt30 and since the bottom edge of the skirt 40 and the bottom edges of thenegators 74 and 74' are below this level, the fumes created by thegrinding operation cannot escape thereunder. The fumes are alsoprevented from escaping through the slot 72 because of the sealingrelation between the negators 74 and 74' and the skirt 40. The aperture64 is likewise sealed by the engagement of the flaps 66 and the insertedwork holding chuck. The aperture 24 may also be sealed by providing aresilient collar such as rubber or plastic around the abrading cupsupport arm or by providing similar flaps as in aperture 64.

In operation, the work holding chuck is inserted through the aperture 64and locked in position. The abrading tool and support arm are insertedthrough the aperture 24 and when the support arm 46 makes its abradingsweep (assume clockwise in FIGURE 3), it will abut against one side ofthe aperture 24 and cause the pan 14 and attached support arm 46 torotate clockwise about the projection 33. The spools 62 and 62' whichare rotatably secured to the support arm 46 will thus move clockwisecircumferentially. Since the skirt 40 and attached cover 42 cannotrotate because of the fixed chuck in aperture 64, the negators 74 and74' will unroll and roll up respectively to maintain the slot 72 sealedfrom the atmosphere. The relative movement between the bottom of theskirt 40 and the pan 14 will not be hindered by an accumulation ofground partic es because the oil resupply line 36 and exhaust 39 willmaintain the proper level and quality of oil. The use of negatorsprovides opposed compensators which protect the surrounding area fromfumes created by the grinding operation and will not cause anyappreciable drag on the sweep generator motor.

What has been set forth above is intended primarily as exemplary toenable those skilled in the art in the practice of the invention and itshould therefore be understood that, within the scope of the appendedclaims, the invention may be practiced in other ways than asspecifically described.

What is new and therefore desired to be protected by Letters Patent ofthe United States is:

1. A housing for enclosing a grinding chamber comprising a generallyhorizontal oil pan, a vertical flange circumscribing said oil pan, avertical ridge on said pan spaced inwardly of said flange and definingan annular chamber therewith, said chamber adapted to be filled withoil, a rigid support member extending vertically upwardly from pan, abearing surface terminating the end of said rigid support member, asupport arm aflixed to said support member and having an inner enddisposed approximately centrally over said pan member, a top coverrotatably supported at said inner end, a skirt depending from said topcover and having a lower end disposed in said annular chamber immersedin said oil and spaced from the oil pan, said skirt having a slot in itsperiphery, and means attached to said skirt in sealing relation oversaid slot for substantially frictionless movement of said skirt ineither direction.

2. A housing for enclosing a grinding chamber comprising a generallyhorizontal oil pan, a vertical flange circumscribing said oil pan, avertical ridge on said pan spaced inwardly of said flange and definingan annular chamber therewith, said chamber adapted to be filled withoil, a ridge support member extending vertically upwardly from pan, abearing surface terminating the end of said rigid support member, asupport arm afiixed to said support member and having an inner enddisposed approximately centrally over said pan member, a top coverrotatably supported at said inner end, a skirt depending from said topcover and having a lower end disposed in said annular chamber andimmersed in said oil, said skirt having a slot in its periphery, and.means attached to said skirt in sealing relation over said slot forsubstantially frictionless movement of said skirt in either direction,said means comprising first and second rotatable takeup spools extendingdownwardly from said sup port arm, a first biasing member having a firstend attached to the circumference of said skirt and a second end affixedto and wrapped about said first spool, and a second biasing memberhaving a first end attached to the circumference of said skirt and asecond end affixed to said second spool.

3. The apparatus recited by claim 2 wherein said first and secondbiasing members provide a uniform bias throughout the rotatable movementof said skirt.

4. A grinding housing in combination with a grinding tool assembly, saidhousing comprising a top member, support means on said grinding toolassembly for rotatably suspending said top member, a coolant pandisposed below and spaced from said top member, a skirt dependingdownwardly from said top member and rotatable therewith, said skirthaving a length less than the distance between said top member and saidpan whereby the lower edge thereof is in spaced relationship with saidpan, a plurality of spaced members extending upwardly from said pan andon both sides of the skirt defining a chamber therebetween receivingsaid lower edge, fluid in said 6 chamber forming a liquid seal betweenthe interior of the housing and the atmosphere.

5. The housing recited in claim 4 wherein said skirt has an elongatedopening intermediate its length and a pair of biasing members havingfirst ends respectively attached to either side of said opening andhaving their other ends attached to said frame.

References Cited UNITED STATES PATENTS 2,589,488 3/1952 Fowler 51-1242,747,339 5/1956 Schelling 51--124 2,757,487 8/1956 Coburn 51272 X3,281,006 10/1966 Wei 220-4 JAMES L. JONES, JR., Primary Examiner US.Cl. X.R. 51-268

